doc: be less dramatic about changeset immutability
Quoting Phillipe: "This is not a Tolkien Novel".
--- a/docs/index.rst Tue Aug 29 16:14:15 2017 +0200
+++ b/docs/index.rst Tue Aug 29 16:14:28 2017 +0200
@@ -18,8 +18,7 @@
With core Mercurial, changesets are permanent and immutable. You can
commit new changesets to modify your source code, but you cannot
-modify or remove old changesets—they are carved in stone for all
-eternity.
+modify or remove old changesets.
For years, Mercurial has included various extensions that allow
history modification: ``rebase``, ``mq``, ``histedit``, and so forth.